Mechanical Properties of Maize Stalks from the Plant Introduction Collection 1

The Plant Introduction (PI) Collection of maize ( Zea mays L.) contains accessions with stronger stalk rinds than the check hybrid ‘AES704’. Stalk rind “thickness” was based on strength of the sclerified hypodermal area measured in tension. Many accessions selected as being superior were based on means from at least 2 years of tests. There was a significant year effect in measuring stalk rind “thickness.” Accessions having high mean stalk rind “thickness” were found in accessions from diverse regions. The largest group of accessions having superior stalk rind “thickness” came from Ethiopia. Flint, dent, floury, and popcorn types were represented among the varieties with a high mean stalk rind “thickness.” The PI 414178 ‘Breve Padilla White‘ from Texas had the highest value for stalk rind “thickness” relative to AES704. Stalk rind “thickness” was highly correlated with stalk diameter among genotypes. The simple correlation coefficients were r = 0.53, 0.85, 0.85, 0.82, and 0.72, for the years 1973, 1975, 1976, 1977, and 1978, respectively. The theoretical stress at which localized buckling of the rind occurs or critical compressive stress (Nx) was calculated from the ratio of stalk rind “thickness” to stalk diameter. Nx ranged from 71 to 382 MPand was always highly correlated with stalk rind “thickness” but not necessarily with stalk diameter.